1. Field of Invention
The present invention relates to a conductive circuit structure in which circuit conductors such as bus bars which are used in the connection of a power supply circuit and the like of, for example, an automobile and are disposed in a resin substrate are exposed in the longitudinal direction.
2. Related Art
Conventionally, various conductive circuit structures have been proposed in which bus bars, i.e., narrow strip-shaped flat rectangular conductors, are insert-molded in an insulating synthetic resin. The bus bars are able to allow large currents to flow as compared with electric wires, and are mainly effective for power supply.
By way of an example of a conventional conductive circuit structure, FIGS. 5A and 5B illustrate a structure in which ends of bus bars are made to project from a resin material so as to be formed as portions of terminals (refer to the prior art in JP-A-11-77736).
Namely, two bus bars are arranged in parallel inside a rectangular flat resin substrate 41, and one terminal portion of each bus bar 42 projects from one end portion of the resin substrate 41 to the outside and is formed as a tag terminal 42a. The other end portion side of the resin substrate 41 continues integrally to a flange portion 43 for fixing and a housing 44 on the flange portion, and the other terminal portion (not shown) of each bus bar 42 is led into the interior of the housing 44.
The resin substrate 41 is cut away in a longitudinally intermediate portion of the resin substrate 41, and this portion 42a of each bus bar 42 is in a slightly exposed state. This is because, at the time of insert-molding the bus bars 42, the bus bars 42 are fixed by clamping the bus bars 42 by a molding metal mold (not shown). To prevent this exposure, a method is disclosed in JP-A-11-77736 in which the bus bars 42 are fixed by a holder (not shown), and resin pouring is effected in a state in which the holder is clamped by a mold.
In addition, JP-A-10-249882 discloses a conductive circuit structure in which bus bars are insert-molded in a resin material, and end portions of the bus bars are bent orthogonal and are exposed to the outside from an end portion of the resin material so as to be formed as terminal portions.
In addition, an arrangement in which the bus bars, instead of being insert-molded, are fitted in grooves in a resin substrate and are routed in a required configuration is applied to a bus bar wiring board (not shown) of an electrical connection box.
However, with the above-described conventional conductive circuit structure in which the bus bars are insert-molded, the bus bars 42 can be connected to circuits and electrical components on the mating side only at the end side of the resin substrate 41, so that there has been a problem in that the degree of freedom of circuit design is limited. In addition, there has been another problem in that the number of electrical components and auxiliary equipment that are connected is limited.
Particularly in circuits including those of an instrument panel of an automobile, a need for connection of optional parts and circuit changes as well as a need for add-on circuits (additional circuits) attributable to them are likely to occur. Therefore, in correspondence with these needs, there has been a strong demand for a conductive circuit structure which is capable of easily and reliably effecting connection with bus bar circuits for power supply and the like with a certain degree of freedom in the connecting position.
In addition, with the conductive circuit structure in which the bus bars are routed on the resin substrate without being insert-molded, there has been a problem in that the strength of fixation of the bus bars is weak and the bus bars cannot be fixed unless the resin substrates are laminated, and there has been an additional problem in that the insulation between the exposed bus bars is liable to deteriorate.
In view of the above-described aspects, an object of the invention is to provide a conductive circuit structure which is capable of allowing circuit conductors such as bus bars to be easily connected to the circuits and the like on the mating side even at portions other than the end portion of the resin substrate so as to improve the degree of freedom in circuit design and the like, which makes it possible to increase the number of electrical components and the like to be connected, which makes it possible to increase the strength of fixation of the circuit conductors and to improve the insulation between the circuit conductors.
To attain the above object, the invention basically provides a conductive circuit structure in which an electrically conductive circuit conductor is disposed on an insulating resin substrate, characterized in that an electrically conductive surface of the circuit conductor is exposed from the resin substrate continuously in a longitudinal direction, and both side portions of the conductive surface are covered and fixed by collar walls of the resin substrate.
It is also effective if a plurality of the circuit conductors are arranged in parallel, and the conductive surface of each of the circuit conductors is exposed from the resin substrate continuously in the longitudinal direction.
In addition, it is also effective if the circuit conductor is a bus bar.
In addition, it is also effective if the circuit conductor is insert-molded in the resin substrate.
In the present invention, it is also effective if the circuit conductor is an electrically conductive resin material.
It is also effective if the conductive resin material is poured and solidified in a groove portion having collar walls in the resin substrate.
In addition, it is also effective if a contact terminal on a mating circuit side or electrical component side is brought into contact with the conductive surface of the circuit conductor.
In addition, it is also effective if a second circuit board is laminated on the resin substrate, an insertion hole for allowing the conductive surface of the circuit conductor to be exposed is provided in the second circuit board, and the contact terminal is inserted in the insertion hole so as to be brought into contact with the conductive surface of the circuit conductor.
In addition, it is also effective if other contact terminals on the mating circuit side or electrical component side are brought into contact with circuits of the second circuit board.